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                                                                     Exhibit 5.1
             [AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P. LETTERHEAD]

                               September 23, 1999


Century Business Services, Inc.
6480 Rockside Woods Boulevard, South
Suite 330
Cleveland, Ohio  44131

Ladies and Gentlemen:

         We have acted as counsel to Century Business Services, Inc., a Delaware
corporation (the "COMPANY"), in connection with the filing of a registration
statement on Form S-4, Registration No. 333-81039 (as amended, the "REGISTRATION
STATEMENT"), with the Securities and Exchange Commission pursuant to the
Securities Act of 1933, as amended (the "SECURITIES ACT"), and the rules and
regulations promulgated thereunder. The Registration Statement relates to an
aggregate of up to 15,000,000 shares (the "SHARES") of common stock, par value
$0.01 per share ("COMMON STOCK"), of the Company, which may be issued by the
Company from time to time in the future on the completion of acquisitions of
assets, businesses or securities ("ACQUISITIONS") or the conversion of or
payment of interest on convertible securities issued by the Company in
connection with such acquisitions of other assets, businesses or securities.

         We have, as counsel, examined originals or copies, certified or
otherwise identified to our satisfaction, of such corporate records, agreements,
documents and other instruments, and such certificates or comparable documents
of public officials and of officers and representatives of the Company, and have
made such inquiries of such officers and representatives, and reviewed such
questions of law as we have deemed relevant, necessary or appropriate as a basis
for the opinion hereinafter set forth.

         In such examination, we have assumed the genuineness of all signatures,
the authenticity of all documents submitted to us as originals, the conformity
to original documents of documents submitted to us as certified or photostatic
copies and the authenticity of the originals of such latter documents. As to all
questions of fact material to this opinion, we have relied upon representations
of the Company.

         Based upon such examination and representations, we advise you that, in
our opinion, when the Registration Statement becomes effective under the
Securities Act, the Shares to be issued in connection with Acquisitions will be
duly authorized and, after the Company's Board

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AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.

Century Business Services, Inc.
September 23, 1999
Page 2

of Directors specifically approves each Acquisition and when the Shares are
issued in accordance with the terms of each such Acquisition, such Shares will
be validly issued, fully paid and non-assessable.

         In connection with the opinion expressed above, we have assumed that,
at or prior to the time of the delivery of any Shares, (i) the Board of
Directors of the Company (and, to the extent required by applicable law, the
stockholders of the Company) shall have duly authorized and approved the
Acquisition pursuant to which such Shares are being issued and such
authorizations shall not have been modified or rescinded, (ii) there are
sufficient authorized and unissued shares of Common Stock to satisfy such
issuance, (iii) the Registration Statement shall have been declared effective
and such effectiveness shall not have been terminated or rescinded, (iv) there
shall not have occurred any change in law affecting the validity or
enforceability of such Shares and (v) there shall not have occurred any change
in the Certificate of Incorporation or Bylaws of the Company. We have also
assumed that the consideration received by the Company for such Shares in any
such Acquisition is lawful consideration and equals or exceeds in value the
aggregate par value of the Shares issued and that neither the issuance or
delivery of such Shares, nor the compliance by the Company with the terms of
such Shares, will violate any applicable law or will result in a violation of
any provision of any instrument or agreement then binding upon the Company, or
any restriction imposed by any court or governmental body having jurisdiction
over the Company.

         The foregoing opinion is limited to the corporate laws of the State of
Delaware and the Federal laws of the United States of America, and we express no
opinion as to the effect on the matters covered by this letter of any other law.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement. In addition, we consent to the reference to us under the
caption "Legal Matters" in the prospectus forming a part of the Registration
Statement.

         This opinion is rendered solely to you in connection with the above
matter. This opinion may not be relied upon by you for any other purpose.

                                Sincerely yours,


                                /s/ AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.

                                AKIN, GUMP, STRAUSS, HAUER & FELD, L.L.P.


